alpha-aryl-beta-alkoxyacrylonitriles and method of preparing same



Patented Sept. 2, 1952 2,609,384 A um'rsosrarss PATENT if 'orFic f 'a AaYL-e-ALKOXYACRYLONITRILEs AND, v

METHQD OF PREPARING SAME v *Pe ter'Byrom Russell, Tuckahoe, N. Y., and Nor- I man Whittaker, London, England, assignors to; 1

' Burroughs Wellcome & 00. (U. S. A.) Inc.; Tuckahoe, N. Y., a corporation of Newiorlr No Drawing. Application December? Serial No. 203,792.55

Y This invention relates a1; new a-aryl-fialkoxy-acrylonitriles and to an improved process for their preparation.

These compositions are important intermediates for the preparation of chemotherapeutic agents, particularly those of the 5-aryl-4-aminopyrimidine series (as described by I-Iitchings, Russell and Falco in U. S. Application S. N. 74,462), Their importance derives from the fact that 11- aryl- 3-hydroxyacrylonitriles condense poorly, or, if substituted by alkyl oraryl groupings in the 3. position, may fail to condense with guanldine or amidines, Whereas the corresponding B-alkoxy derivatives react to form the desired pyrimidines in good yield.

The new compounds of the present invention may be illustrated by the following general formula:

(EN (EN (EN I II III give some of the desired, substance; howevensuperior yields are obtainable through the use of (1) a diazoalkane or 2) the new-method described herein in which the alkylating agent is an orthoester. In view of the hazards and dimculties connected with the use of'diazoalkane's,

particularly on a manufacturing scale, the emof the reaction, and of any excessand unreacted orthoester. The residual alkoxynitrile-(III), may, for certain purposes, be used in the crude state and may crystallize spontaneously and may at times be isolated by distillation, preferably in vacuo. v 4

V The reaction of the fi-hydroxynitrilewith an orthoester may be illustrated as follows; I

' Q2 +R It is understood that the invention is in no way limited or bound by this explanation of the course of the reaction, whichds advanced for illustrative purposes only. I

Since the alkyl radical (R, III) does not participate in the further reaction ofthe alkoxy nitrile all lower alkyl' radicals are essentially equivalent. Furthermore, theorthoesters of various acids are equally reactive. Therefore a Wide choice of ortho ester is-available, and preference for a particular orthoester is determined by availability and cost.

The following examplesare given to illustrate the manner in whichthe invention may be carried'out, but it is to be understood that the scope of the invention is defined in the claims.

EXAMPLE 1 v I a-pechlorophenyl-fir-ethoxyacrylonitrile I a-Formyl-p-chlorophenylacetonitrile (20 g.) was heated over a free flame with ethylorthoformate (40 ml.). The mixture of ethyl alcohol and ethyl fo'rmate evolved was collected. After about one hour 12A g. had been collected and the distilling temperature rose above 80; the reaction was complete. Thev excess ethylorthoformate was then removed in vacuo, and the residue distilled. Itgave a colorless oil (17.0 g,; B. P 132133/0.0l mm.) which solidified on cooling. i

,Calcd. for C11H10ONCl-I C, 63.6; H, 4.8; N, 6.8; CI, 17.1.' Found: C, 63.1; H, 50; N63; C1. 16.6.

' EXAMPLE- 2 2,4 -dichlorophenyl-fi methiowyacrylonitrile a-Formyl-2,4-dichlorophenylacetonitrile (10 g.) andr methylorthoacetate ml.) were heated together as in the previous example. When no more methanol'and methylacetatewere evolved,

a jArCCN i III 10 theexcess.methylorthoacetate was removed in p 3 vacuo and the residue crystallized. After recrystallization from ethanol it formed needles M. P. 105-107. (Undepressed on admixture with the product obtained by action of diazomethane on the same ketonitrile) FoundzC, 53.0; H, 3.0;N, 6.4.

Oalcd. for CmHsONCIz: C, 52.9; H. 25; N, 6.2.;

EXAMPLE 3 a.-Acetyl-p-chlorophenylacetonltrile and ethylorthoformate were reacted together as above,

After removal of the excess orthoester the product crystallized. Recrystal-lized from ethanol, it. formed prisms M. 'P. 110". Boils at 128-130 at' Calcd. for C12HizONCl: -\C,' 65.2; Found: C, 65.3; H, 5.3; N, 6.1.

EXAMPLE4 a-3',4'-dichZorophenyl-p-metho;vyp-methylacrylonz'trile The corresponding k-eto nitrile (12 g.) was heated with methyl orthoacetate (24 ml.) in the usual manner. The residue after removal of excess of the orthoester solidified. Recrystallized from ethanol, it formed plates M. P. 71-74.

AnaL': Oalcd. for CiiHsONCIz; N, 5.8. Found: N, 6.0.

EXAMPLE 5 a- (3,4-dichlorophenyl) -,3-etho:cy-5-me;thylacrylonitrile a-Acetyl-3,4-dichlorcxphenylacetonitrile (5.5 g.) was treated with 110 ml. of ethylorthoformate. Removed of volatile material and of excess orthoester, gave a solid residue. ,Recryst-allized from ethanol it formed needles M. P. 90f-93".

Anal: Calcd. for C12H11ONC12Z N, 5.5%. Found; N, 5.6%.

EXAMPLE? I a m-ChZorophenyZ-p-n butoryacrylonitrile a-Propionyl-p-chlorophenylacetonitrile 32 gms. refluxed with 64 cc. ethylorthoformate. When the low boiling material was evaporated the excess orthoformate' was removed. The d-p-chlo- 4 rophenyl-fl-ethoxy -;3- ethylacrylonitrile formed a heavy oil which on condensation with guanidine gave 2,4-diamino-5-p-chloropheny1-6-ethylpyrimidine.

EXAMPLE 9 a.Phenyl-p-ethoxy-p-ethylacrylonitrile a-Propionylphenylacetonitrile (40 gm.) heated with gm. of ethyl orthof-orm-ate as above. The product was obtained after removal of the ethylformate and ethyl alcohol as a thick oil.

EXAMLE 10 a-p-ToZyZ-p-methoxy-p-methylacrylonitrile a-Acetyltolylacetonitrile (15 gms.) heated with 30 ml. of methyl orthoacetate. The low boiline material was removed as it was formed and finally the orthoacetate was removedin vacuo. The product formed a thick on.

a-Formyl-p-chlorophenylacetonitrile (18 g.) was heated with methyl orthopropionate (35 mls.) over a free flame. The methyl propionate and methyl alcohol boiled about 70. The residue was freed from theorthoester in vacuum and the product formed a thick oil which crystallized; M. P. ca.

. EXAMPLE 12 Prepared from a-caprylylp -chlorop'heny1- 'acetonitrile and ethylorthoformate as above. The product was a heavy uncrystallizable oil.

EXAMPLE 13 p a-PhenyZ-p-n-amyloscy-p-methylacrylonitrile Prepared from a-acetylphenylacetonitrile and n-amylorthoformate in the usual manner. The product formed a heavy uncrystallizable oil.

EXAMPLE 14 a-Phenyl-p-n-propo:1:y-o-propylacrylonitrile Prepared as the above from a-butyrylphenylacetonitrile and n-propylorthoformate. It was a thick oil.

EXAMPLE 15 'a-p-C'hlomphenyl-fi-ethoxyqcrylonitrileP d'sz'ng ethyl orthoacetate Recrystallized a-formyl-p-chlorophenylacetonitrile (20 g.) and ethyl orthoacetate (50 ml.) were heated under a free flame, collecting the mixture (15 g.) of ethyl acetate and ethyl alcohol produced. After 1 hour, excess of reagent was removed by evaporation in vacuo and, by distillation, a-p-chlorophenyl-p-ethoxyacrylonitrile (17.9 g.), B. P. 132-133/0.04 mm., was obtained.

When reacted with guanidine this gave 2:4- diamino-5-p-chlorophenylpyrimidine (15 g.), M. P. 194-195, unchanged on mixing with the pyrimidine derived from the product of Ex:- ample 1. l j d We claim:

1.The process which comprises reacting an m-aryl-a-acylacetonitrile (tautomeric with an aaryl-fl-hydroxyacrylonitri1e) with an orthoester, said reaction being carried out by heating a mixture of the reactants at a temperature not exceeding the boiling point of the orthoester, and in a manner to effect the continuous removal 5 of the volatile products of the reaction, and then removing the excess of orthoester by distillation, preferably under reduced pressure, with recovery of the a-aryl-fi-alkoxyacrylonitrile. 2. A substance of the formula in which Ar is selected from the class consisting of phenyl and halophenyl radicals, R is a lower alkyl radical and R1 is selected from the class consisting of hydrogen, and lower alkyl radicals.

3. a p Chlorophenyl B ethoxy l3 ethylacrylonitrile 6 4. a p Chlorophenyl p ethoxy p methylacrylonitrile.

5. a 3,4' dichlorophenyl {i ethoxy B methylacrylonitrile.

6. a 3,4 dichlorophenyl 5 methoxy p methylacrylonitr'ile.

Keller:

PETER BYROM RUSSELL. NORMAN WHITTAKER.

REFERENCES CITED The following references are of record in the file of this patent:

Chemical Abst.,

v01. 31, col. 6215 

2. A SUBSTANCE OF THE FORMULA 